Continental-scale patterns of extracellular enzyme activity in the subsoil: an overlooked reservoir of microbial activity
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Dove_2020_Environ._Res._Lett._ ...
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Author
Dove, Nicholas CArogyaswamy, Keshav
Billings, Sharon A
Botthoff, Jon K
Carey, Chelsea J
Cisco, Caitlin
DeForest, Jared L
Fairbanks, Dawson
Fierer, Noah
Gallery, Rachel E
Kaye, Jason P
Lohse, Kathleen A
Maltz, Mia R
Mayorga, Emilio
Pett-Ridge, Jennifer
Yang, Wendy H
Hart, Stephen C
Aronson, Emma L
Affiliation
Univ Arizona, Dept Soil Water & Environm SciUniv Arizona, Dept Ecol & Evolutionary Biol, Sch Nat Resources & Environm
Issue Date
2020-10-09Keywords
acid phosphatasebeta-glucosidase
N-acetylglucosaminidase
critical zone
ecological stoichiometry
extracellular enzymes
microbial ecology
phospholipid fatty acids
subsoil
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IOP PUBLISHING LTDCitation
Dove, N. C., Arogyaswamy, K., Billings, S. A., Botthoff, J. K., Carey, C. J., Cisco, C., ... & Aronson, E. L. (2020). Continental-scale patterns of extracellular enzyme activity in the subsoil: an overlooked reservoir of microbial activity. Environmental Research Letters, 15(10), 1040a1.Journal
ENVIRONMENTAL RESEARCH LETTERSRights
© 2020 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Chemical stabilization of microbial-derived products such as extracellular enzymes (EE) onto mineral surfaces has gained attention as a possibly important mechanism leading to the persistence of soil organic carbon (SOC). While the controls on EE activities and their stabilization in the surface soil are reasonably well-understood, how these activities change with soil depth and possibly diverge from those at the soil surface due to distinct physical, chemical, and biotic conditions remains unclear. We assessed EE activity to a depth of 1 m (10 cm increments) in 19 soil profiles across the Critical Zone Observatory Network, which represents a wide range of climates, soil orders, and vegetation types. For all EEs, activities per mass of soil correlated positively with microbial biomass (MB) and SOC, and all three of these variables decreased logarithmically with depth (p< 0.05). Across all sites, over half of the potential EE activities per mass soil consistently occurred below 20 cm for all measured EEs. Activities per unit MB or SOC were substantially higher at depth (soils below 20 cm accounted for 80% of whole-profile EE activity), suggesting an accumulation of stabilized (i.e. mineral sorbed) EEs in subsoil horizons. The pronounced enzyme stabilization in subsurface horizons was corroborated by mixed-effects models that showed a significant, positive relationship between clay concentration and MB-normalized EE activities in the subsoil. Furthermore, the negative relationships between soil C, N, and P and C-, N-, and P-acquiring EEs found in the surface soil decoupled below 20 cm, which could have also been caused by EE stabilization. This finding suggests that EEs may not reflect soil nutrient availabilities deeper in the soil profile. Taken together, our results suggest that deeper soil horizons hold a significant reservoir of EEs, and that the controls of subsoil EEs differ from their surface soil counterparts.Note
Open access articleISSN
1748-9326Version
Final published versionSponsors
U.S. Department of Energyae974a485f413a2113503eed53cd6c53
10.1088/1748-9326/abb0b3
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Except where otherwise noted, this item's license is described as © 2020 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.